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Discussion Starter · #1 · (Edited)
hi,
I tried to mix my own micro ferts and I am now running (after some weeks dosing) in some problems.

Plants like Ludwigias, Limnophilia are growing fast and dont show much deficieny:

- but my Rotalas are getting dark green leafs and the Didiplis (in the same tank) bends the leafs down:

Nesea Golden looks pretty worst :p :


.
Measured nutritions in the water coloumn: 24ppm Ca, 8ppm Mg, 25ppm Nitrate, 12ppm potassium, 1ppm Po4.
(Increasing NPK didnt fix anything. Last week, I also boosted the GH and dosed additional calcium + Mg, but doing so also hasnt fix anything).

So I can meanwhile rule out:
Ca, mg, Nitrate, potassium, Po4, Co2

The problem has for sure something to do with my micro fert mix and the traces ratio,
The traces mix adds daily (I increased last week B, zn, Cu and the Ludwigias response was good - but the other plants have not responsed well):
0,06ppm Fe (1:1:1 Fe-EDTA, Iron(III)citrate, Iron(II)Gluconate)
0,02ppm EDTA-Mn
0,004ppm Boron
0,0028ppm EDTA-cu
0,0024ppm EDTA-zn
0,0008ppm Mo
0,0002ppm Ni
0,00014ppm co
0,00012ppm li
0,00010ppm al
0,00010ppm va
What do you think is too high or too low in my fert mix and could cause such problems like shown in the pics?

I also have co, al, li,va in it, but I am no longer sure if those "so called benefical traces" are really benifical at last and if they could cause some issues, too.
What do you think?
 

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The levels of traces you are dosing are not into the toxic range and the symptoms you have are not toxicity symptoms. Toxicity symptoms from too many traces usually show up as damage on the new and older growth. Trace toxicity makes the plants in the tank look like there are many deficiencies at the same time (there can only be one deficiency at any given time so this is a clear sign of a toxicity).

Some plants, particularly rotalas are more sensitive to iron deficiency than others and usually display iron deficiency symptoms before other plants. The symptoms of iron deficiency are white/pale green new leaves. The symptoms in red plants are similar except because of the red base color these plants look pink until the deficiency becomes severe. This is why your Rotala is turning green/white in the new growth.

Some species of plants, particularly Ammania species also develop slightly twisted newer leaves when iron deficient. Also, Nesea is no longer a recognized name, it was changed to Ammania recently. Here is an example of iron deficiency in Ammania gracilis: http://deficiencyfinder.com/?page_id=125

In fact, if you page through some of the iron deficiency entries I have on my deficiency site you should start seeing the pattern: www.DeficiencyFinder.com

In addition, an iron deficiency makes sense since 0.06 ppm Iron is not very much especially when 2/3rds of the iron you are adding are chelated by organic chelates like citrate and gluconate. These chelators do not protect the iron for very long before it is broken down or precipitated out in the water column. The EDTA is a much better chelator and will hold on to iron in its Fe2+ state for much longer so you are really only adding 0.02 ppm of iron that won't break down for a few days with each dose.

Since you are mixing your own micros (and by the way well done! Not many people do) you can easily increase the concentration of iron you are adding. I'd double it if you are going to keep the 1-1-1 ratio. Add 0.12 ppm (or even a little more 0.15 ppm) a day and keep adding the other micros at the same dose they are added now. Iron doesn't start to become toxic until it is about 1.5 ppm. The studies I read also used non-chelated iron dosed as FeCl3 and FeSO4 which is much more toxic to plants than chelated iron.

Iron is often depleted quickly in a heavily planted tank like yours.

Co, Al, Li, Va can cause issues if they are too high, particularly Al, but if the concentrations you are dosing them at are correct then I doubt they'd cause any problems.

How are you weighing out the micros by the way? Do you have a very accurate digital scale or are you diluting to reach the concentrations above?
 

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Discussion Starter · #3 · (Edited)
Very good point with the iron and I have a general question about iron toxidity, too:
I dosed in past strong chelates like FE-HEEDTA, FE-DTPA, FE-EDDHA and was getting in the long run pale looking plants. My Boraras naevus were no longer swimming much around if there were 0,4ppm HEEDTA/DTPA/EDDHA iron in the water coloumn. The water was certainly somewhat discoloured (Fe-EDDHa pinkish the water).
My feelings in past were that you can not dose FE-EDDHA much higher than 0,02ppm daily, because small fish like Boraras seems to be sensitive if using EDDHA chelator. I was also not sure if high FE-DTPA levels around 0,3-0,4ppm could do some more harm in compare to high Iron(II)gluconate levels and decided weeks ago to drop using those strong chelates.
So my question is,
is there any difference in iron toxidity depending on used chelates?

My idea for the new traces mix was to build it in future around the fully biodigradable Fe-IDHA instead.
Unfortunatly Fe-IDHA is difficult to get and so I temporary switched to the current 1:1:1 solution based on Fe-EDTA, Iron(III)citrate, Iron(II)Gluconate.

And I guess, you are right that my current iron dosing may be too lean for such weak chelates.
I will increase iron to 0,12ppm like you recommend, but what about Manganese?
Should I also increase Mn to 0,04ppm? (to manage 1:1,5 - 1:2,5 Fe:Mn ratio)

How are you weighing out the micros by the way? Do you have a very accurate digital scale or are you diluting to reach the concentrations above?
I have a very accurate digital scale and dillute the ferts in destilled water.
So it is a liquid fertiliser. I reduced the ph with citric acid to Ph 4,5 - I think this should be ok, to keep the chelates stable - or?
 

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I dosed in past strong chelates like FE-HEEDTA, FE-DTPA, FE-EDDHA and was getting in the long run pale looking plants.
This is exactly what iron toxicity looks like. Too much iron blocks plants from using sulfur and sulfur deficiencies make plants look pale (similar to iron deficiencies). People seem to often over dose iron, then see yellowing plants and mistake iron toxicity for iron deficiency.

My Boraras naevus were no longer swimming much around if there were 0,4ppm HEEDTA/DTPA/EDDHA iron in the water coloumn. The water was certainly somewhat discoloured (Fe-EDDHa pinkish the water).
How often were you dosing 0.4 ppm? If you break it up to smaller doses 3x a week or so it should be better. I'd say about 0.2 ppm every other day should be safe. Though I must admit I have not personally used EDDHA before so I do not know if that contributed to the discoloration or pale plants. I doubt it is a problem though since many horticultural places use it without issues. I think the problem you had was probably just too much iron too quickly. So you just need to find a middle ground between what you were dosing and what you are dosing now.

My feelings in past were that you can not dose FE-EDDHA much higher than 0,02ppm daily, because small fish like Boraras seems to be sensitive if using EDDHA chelator.
Again, I don't have any first hand experience with EDDHA chelated iron or the toxicity of it, though from the studies I have read all chelated metals seem to be less toxic by quite a large factor. For example copper becomes 10-1000 times less toxic when it is chelated with EDTA vs. when it is not chelated (CuSO4). Though I haven't read any studies directly comparing the toxicity of chelated iron vs. unchelated iron I would assume it follows a similar trend. And moreover, non-chelated iron doesn't start reaching toxic concentrations until it is over about 1.5 ppm so 0.02 ppm seems very low. Where did you read 0.02 ppm a day?

I was also not sure if high FE-DTPA levels around 0,3-0,4ppm could do some more harm in compare to high Iron(II)gluconate levels and decided weeks ago to drop using those strong chelates. So my question is, is there any difference in iron toxidity depending on used chelates?
0.3-0.4 ppm at any given time should not be toxic. Since DTPA is the best chelator listed here, if you are adding 0.3-0.4 ppm every day or every other day then there seems to be a good chance it could build up in your tank and reach troublesome levels (water discoloration and affect fish and plants).

Unfortunately toxicity studies are few and far between and I have not come across any studies that specifically compared the toxicity of each of the iron chelates. So I cannot say for certain if one type of chelator is more or less toxic than another. I don't think the toxicity of any one of the chelated iron products should be less than the known toxicity values for unchelated iron dosing (about 1.5 ppm).

My idea for the new traces mix was to build it in future around the fully biodigradable Fe-IDHA instead. Unfortunatly Fe-IDHA is difficult to get and so I temporary switched to the current 1:1:1 solution based on Fe-EDTA, Iron(III)citrate, Iron(II)Gluconate.
I have not heard of IDHA before. If it has been around for a while, then it certainly isn't very common.

All the chelated iron products should be bio-degradable. The idea with gluconate and citrate iron is that when plants absorb iron and transport it inside their body they cannot transport ionic iron in the 2+ or 3+ state. It must be bound to an organic molecule. In most plants it is bound and transported inside the plant as Fe-citrate or Fe-gluconate. These molecules are extremely weak chelators and do not really chelate iron very well. The idea behind using these chelates is that supposedly plants *should* find it easy to take them up and transport the entire complex around inside the plant. However, I have my doubts. I haven't read any studies that state plants can absorb Fe-gluconate or Fe-citrate as an entire molecule. I also haven't really read any studies that say adding this form of iron helps plants grow better.

I will increase iron to 0,12ppm like you recommend, but what about Manganese?
Should I also increase Mn to 0,04ppm? (to manage 1:1,5 - 1:2,5 Fe:Mn ratio)
I'd keep the manganese levels as you have them. Plants do not need very high levels of most of the micro nutrients to prevent deficiency. Also, maintaining specific ratios of micros to other micros like iron to manganese is not supported by the articles I have read. Plants do not take up micros in a linear fashion. The rate they take up nutrients and the rate they use them varies and does not support the need to maintain precise ratios between each micro.

Also one other thing. I noticed you are adding nickle to your micro nutrient mix. While nickle is an essential nutrient which plants cannot live without out of all essential nutrients nickel is needed in the smallest amounts, plants can take up nickel at concentrations as low as 4.4 ppb (parts per billion). It was not until the 1970s that powerful enough analytic techniques were developed to detect nickel's vital role. That said, nickel deficiencies are virtually unseen outside the lab and when seen tend to happen at above pH 6.7. So there really is no pressing need to add nickle to your micro mix.

I reduced the ph with citric acid to Ph 4,5 - I think this should be ok, to keep the chelates stable - or?
Once mixed chelated compounds will be degraded by bacteria and other natural processes. The best way to store them is in dry form, though they will keep for a while in solution. A low pH should help prevent bacteria and keep the metals soluble.
 

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So you guys are using chelating compounds as time release agents..... Interesting.

Just curious: Are there any studies handy about the metabolic degradation of these agents in the water column over time?
 

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Discussion Starter · #6 · (Edited)
The DTPA dosing was so that there were permanently ~0,4ppm iron in the water coloumn.
Doing so hasnt worked good and you overdose the plants with (DTPA) iron by doing so.
About EDDHA: Dosing more than 0,02ppm Fe-EDDHA did not do any direct harm to fish and i do not say it is any toxic -but- the fish change their natural behaviour under EDDHA dosing.
I personally guess, it still has something to do that even 0,02ppm Fe-EDDHA discolours the water.
I never tried dosing 0,1ppm FE-EDDHA daily, because it will tint yours water ugly redbrown and I can tell you the red colour did not go away.
You need to do some large water changes to get ridd off it.

Fe-EDDHa can imo still be used in very tiny amounts.
Even if you still add 0,005ppm daily - you will see (if you are not doing weekly water changes) a slightly water discolourisation.

All the chelated iron products should be bio-degradable.
Just curious: Are there any studies handy about the metabolic degradation of these agents in the water column over time?
Citrate and Gluconate are easy biodegradable
EDTA, EDDHA, DTPA, HEEDTA are known as bad biodegradable (compared to other chelates like IDHA, NTA, GLDA and so on)
Here you can see a 30days comparsion chart:

http://www.fotos-hochladen.net/uploads/chelatecomparemu28yiovlq.jpg

I also haven't really read any studies that say adding this form of iron helps plants grow better.
There was a German university study around Zinc-EDTA, Zinc-EDDHA, Zinc-DTPA and the study has shown that the zn uptake rate depends on the used chelator. The root grow was not the same depending on the used chelator. The zinc was also more or less toxic to the roots, depending on the chelator.
So if chelating agents make some differences on Zn uptake rate - why not on iron, too?

About Fe-IDHA, I still found this agriculture paper where the grow rate was compared to Fe-EDTA:

http://www.fotos-hochladen.net/uploads/idhavsedtaykqpi9smnj.jpg
I personally never used Fe-IDHA under aquatic conditions - but since it is a biodegradable chelator, it is really worth a try.

Also one other thing. I noticed you are adding nickle to your micro nutrient mix.
I am also not sure about Ni,
the only informations I was able to gather was that it enables in some plants the Urease enzyme and should "perhaps" also be benefical in generel for nitrogen uptake, too. Well yesterday I noticed after dosing the old trace mix with all those benefical traces that few minutes later some plants were bending their leafs.
Today I mixed a new bottle with increased iron and temporary removed all benefical traces (ni, co, al, va, li) - just to be sure that nothing from this stuff makes perhaps some hidden trouble.
 

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Has anyone by chance played with weird stuff like propionates, as opposed to weird chelating agents?

I mean, if you want to suck metals out of living things.... I get it. But if you're just going for time release stuff... it sure seems there'd be a cheaper, simpler, more controllable way to do it. Not that I'd know.... I've never even considered it before. Maybe propionates (and similar) are totally impractical.
 

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Discussion Starter · #8 · (Edited)
Yesterday I measured iron and it was 0,08ppm in the watercoloumn.
This is very strange, because my iron dosing was during the last weeks still low.
Neverhteless,yesterday I dosed the new mix and 0,12ppm like recommended.
I measured today again and there are now 0,1ppm iron in the watercolumn. Since citrate/gluconate break down quickly, it just shows the iron (from Fe-EDTA) still accumulates and that the plants dont take up (for some reasons) any iron.

I watched now some fast growing weed like the Heteranthera very close and noticed that the chlorosis did not start from the tip/end - it start from inside the leaf.

http://www.fotos-hochladen.net/uploads/deficiencybjv17zy0g9.jpg
It seems something induced anyhting that reduces the iron uptake and I decided to dose 0,001ppm Zn more, but the Heteranthera showed still very little signs of recover. So I decided to dose also additional 0,05ppm Manganese and 4 hours later the leafs were looking much more green.
Plants like Limnophila Guinea Broad Leaf are known as very sensitive and that they can quickly melt or recover and the Limnophila also appreciated the extra Mn dosing.

My temporary conclusion:
It seems not to work just to increase only Iron.
Manganese seems also be involved, perhaps zn/cu, too
( I am not sure if a higher Cu level could perhaps have some antagonistic effects on iron/manganese uptake)

Well, this certainly opens the question - how to optimize now the other traces dosing rates.
Mn should be added more, the question by all this is still "how much for beeing successfull in the long run".
 

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Well, I've never played with any of this, but, it all strikes me as kind of an odd way to go about time releasing metallic nutrients because chelating agents are used for..... Are you ready for this?..... taking metals out of living organisms!

Is this one of those attempts at "It's so crazy, it just might work"? Or is there actual, hard data, published by sources external to interested parties, showing that this is at all effective? I mean, if this study
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC106148/
happened to be the basis for this whole chelating agent fertilization movement, it isn't exactly a sparkling representative of a great notion, from what I've read thusfar.

BTW, citrate and gluconate are not chelating agents, hence, they are used as delivery systems for living things.

How about something like this, which I mentioned above.
http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=9859059

Or maybe even something really neato & exotic, like this (amphetamine chemists, are you paying attention?).
http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=158176

Furthermore, if one of the EDTA degradation products is ethylenediamine, and that is at all converted to ethylene by way of deamination, then you're looking at a plant killer. Ethylene is the senescence hormone that tells plants to die.
 

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Mac120 - I think that is very interesting. Though I don't think you can draw a valid conclusion on which nutrient was deficient from the rapid doses of different nutrients you did. More time was needed between the different treatments to allow the nutrient to be mobilized and used in the plant. It takes time for plants to absorb, convert, and incorporate metals into proteins. Without waiting more time in between dosing the re-greeing is ambiguous, it could have been from any of the nutrients you added. From previous experience it can take up to 3 days in CO2 injected tanks for increased iron to make a difference and help reverse chlorosis.

Playing devil's advocate it could easily be argued that the greening was caused by the Fe, Zn, or Mn you added in the last day and it just took a few hours to work its magic. This is why it is best to only make one change at a time and wait long enough between. Furthermore, Zn and Mn don't usually show up as uniform pale new growth, that is specifically and uniquely an iron deficiency symptom, so I doubt it was Mn or Zn that caused the greening.

Unfortunately, the only way to get a 100% confirmed answer is to have you repeat the entire problem. To do that you'd have to go back to your original dosing schedule until the plants develop chlorosis again. Then try adding more Mn and wait at least 3 days (if not a week to be sure), if no changes occur then add more iron and see. Or you could start by adding iron first to see if the chlorosis is iron related, then try the Mn out, whichever you want to test first.

misant777 - where would you get those chemicals from at a hobbyist level?
 

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Well since you have me thinking about Mn, Zn and Fe let me explain more about Mn deficiency.

Mn's Role
Mn's main role in photosynthesis is its involvement in the water splitting system of photosystem II. It is also involved in metabolic processes such as respiration, photosynthesis, synthesis of aminoacids and hormone activation. Mn is also used as a cofactor in an enzyme called superoxide dismutase which is an extremely important enzyme that helps stop oxidative damage caused by reactive oxygen species and other radicals that are made by photosynthesis. Therefore, when Mn is deficient it is dangerous for the plant because it affects photosystem II which provides the necessary electrons for photosynthesis and at the same time reduces the plant's ability to prevent damage by reactive oxygen species.

Mn Deficiency
Mn deficiency occurs most often when the pH is between 7.3-8.5, when the CaCO3 levels and organic levels are high. Also, chelated Mn is absorbed by plants more slowly than free Mn ions. Mn is an immobile nutrient, and therefore cannot be transported out of old growth so all effects show up on newer leaves (but not the very newest leaves).

Mn deficiency becomes unmistakable only when the growth rate is extremely slowed down. It shows up as diffuse interveinal chlorosis on young fully formed leaves (which differs from iron deficiency which shows up on the very newest small not fully formed leaves first). Severe necrotic spots or streaks may also form in Mn deficiency. Symptoms often appear first on the middle leaves. In mild cases the symptoms appear on young leaves and disappear as the leaf matures. Young leaves often show a network of green veins in a lighter green background, closely resembling iron chlorosis.

Interestingly, in contrast to iron deficiency the chlorosis from Mn deficiency is not uniformly distributed over the entire leaf and the leaf tissue may rapidly become necrotic.

It can be difficult to tell early Mn deficiency apart from iron deficiency, but late Mn deficiency leaves start dying rapidly and necrotic lesions develop.

Mn Toxicity
Mn can be extremely toxic to plant cells. Toxicity occurs mainly in acidic conditions with low organic content in the environment. Mn uptake does not appear to be tightly controlled.

Toxicity causes plants to slow down their growth rate, but you will also see interveinal and marginal chlorosis in older leaves. Necrotic leaf spots are also very common and so is leaf wrinkling. These symptoms can occur all over the whole plant (new and old growth) but in terrestrial plants is focused mainly in the old growth. Mn toxicity can sometimes appear similar to Fe deficiency due to the chlorosis. Toxicity of Mn is also made worse if other nutrients are in low concentrations (Ca, Mg, K, Fe), and in general higher Ca and Mg levels make micro nutrients less toxic and protect plants.

From:
Handbook of Plant Nutrition by Allen V. Barker & David J. Pilbeam​

From:
Manganese as essential and toxic element for plants: transport, accumulation and resistance mechanisms, by R. Millaleo et al.,​

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My opinion

I do not think you had a Mn deficiency because Mn deficiencies are not common, in planted tanks and more specifically, in low pH environments which have low organic waste levels. By doing frequent water changes, not having a soil substrate and injecting CO2 you essentially keep Mn very soluble in the water column and easy for the plants to absorb.

Also, if you compare your trace mix to CSM+B's formula (a widely used trace mix), you'll see that for every 0.12 ppm of EDTA iron it adds CSM+B adds 0.03-0.04 ppm Mn. So you dosing 0.02 ppm and 0.12 ppm iron (mixed forms) is not that far off. Certainly not enough to cause a deficiency in my opinion.

In addition, I have not been able to find any information supporting the idea that Mn deficient plants are capable of re-greening once Mn has been applied. However, iron deficient plants are frequently noted as being able to re-green to some extent after iron has been replaced in the environment.

Zn really isn't even a contender since its symptoms don't really match at all (inteveinal chlorosis that happens between the midrib and secondary veins and tiny new leaf growth like nitrogen deficiency, sometimes red spots appear on the leaves).

In summary, I think the problem was, in fact, an iron deficiency and it just took a few hours for the plant to absorb, convert and start using the iron.
 

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Discussion Starter · #13 ·
I altered the fertiliser yesterday again:
0,16ppm Fe
0,04ppm Mn
0,18ppm Mg
0,56ppm K
Those 0,16ppm Iron are now from: 0,04ppm Iron-IDHA ; 0,12ppm Iron(II)Gluconate

My Limnophila Genua was looking today a little bit pale, just only 20minutes after dosing it looks again green. The current chelate combination seem too work a lot faster then the old EDTA/Citrate/Gluconate mixture.
I also raised Mg, but I am unsure there and never tracked Mg uptake.
Do you think it is "ok" or did it add perhaps too much Mg in the long run?
(I do not perform weekly water changes)

Toxicity causes plants to slow down their growth rate, but you will also see interveinal and marginal chlorosis in older leaves.
Do you have any closer information about the ppm rate when Mn toxicity happens?
I researched the web, but still found this comment from a duckweed study:

"Wang (1986) conducted 4 day acute and 7 day sub-chronic tests on the effects of manganese on the growth of duckweed (Lemna minor). The study was conducted using tap water at a pH of 7.5 (no hardness or temperature data provided) and the exposure endpoint was growth as indicated by the number of fronds initially and at the end of the exposure period. Twenty colonies of duckweed were studied and an EC50 (reduction in frond growth in 50% of test organisms vs. controls) of 31 mg/L was derived."

Seems 31mg/L (?) is EC50 for duckweed?
Unfortunalty, about other plants i found nothing.
 

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Discussion Starter · #14 · (Edited)
Some new pics how plants response.

Good news: Stargrass + Nesea (Ammania) Golden recovered and I can confirm it was iron deficiency there.
Sp. Golden is meanwhile getting a new strong sideshoot, looks good so far. :) In the second tank the sp. golden looks also a lot better.
Bad news: Rotala Vietnam shows few recover signs, but looks way too small and still poor Rotala overall grow rate.

It seems the problem with the dark green older leafs is also not fixed and Limnophila Genuia shows today some melting :rolleyes: old leafs.
(Nitrogen is 12-15ppm , phosphate 0,2-0,5ppm, potassium ~10ppm)

The plants show daily uptake from: iron, phosphate, potassium
but still use little nitrate. Seems they are somehow limited in their nitrogen uptake - any nutrition that can cause this?
What is with molybdenum , is it perhaps too lean - how much should be daily added?
( I browsed yours deficienyfinder.com and also APC deficieny finder - I can see @APC few molebdenum deficiency thumbails:
http://www.aquaticplantcentral.com/.../browseimages.php?do=browseimages&c=12&page=2
But I cant open the images and get a blank "Php error message". How to get those images in fullsize ??)
 

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Discussion Starter · #16 ·
Well, I meanwhile think that too much copper induces iron deficiency.
After reducing copper, some plants (primary Neseae, stargrass) were doing a lot better, but unfortunaly not Rotalas. Since I can now rule out copper, left is zn, mn, b (mo)
My focus moves first to zn and then, mn and b.

Based on this study I believe the appropriate copper levels are around 0.03 Cu for good long term growth. Anything over that and you should start to see general decrease in growth rate. For zinc 0.08 seems a safe baseline value to shoot for.
Have you ever tested those levels in planted tanks with sensitive plants?
 

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Have you ever tested those levels in planted tanks with sensitive plants?
Nope, I haven't tested the copper level I mentioned above for toxicity effects. As much as I'd love to do the tests, testing out the ranges is beyond my budget/capability since I don't have my own plant lab or access to the right kinds of tests. The best I can do is read through all the literature and come up with general ranges where negative effects should start to affect the plants we keep.

However, if you were to set up the proper test though I suspect that you wouldn't see the plant die or even show negative signs until the concentration of copper got high enough. At concentrations above 0.02 ppm and below the visible-with-the-naked-eye damage concentration I think you'd start to have reduced growth rate or perhaps less chlorophyll produced by some percent. This unseen damage would have to be quantified with the right machine in order to tell by how many percent the growth rate is below normal levels.

An interesting detail to be aware of is that the concentration of copper affects how long the study needs to be to see a difference in growth. For example, using 1.1 ppm copper will affect plants within 24 hours killing them. If you use 0.5 ppm it will take a little longer, 0.25 a little longer still etc until you reach the concentration that has no negative effects on plants. I believe that the concentration with no negative effects is at 0.02 - 0.03 ppm and below. Anything above this level and plants will be stressed by copper and not grow at the maximum rate that they could.
 

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Discussion Starter · #18 ·
I daily dosed up to 0,0056ppm and plants like Limnophilias, Ludwiga, Cryptocorgnye were doing ok. (other plants will not do that good)
High copper levels seem also to enhanced red colurs from Ludwigia Red
(attachment: left pic stock cu dosing -> right pic high cu dosing)
The Ludwigia seems also not to get any chlorosis even at high copper dosing, but you can see that some leafs are bending down. (imo a first sign off too high long term copper dose for Ludwigas)
Green plants instead seem to get chlorosis like seen on Heteranthera. Such copper induced iron chlorosis can be override for some percent by heavy iron dosing, but bottom line is that Copper sensitive plants simply dont like high Cu levels.

The other thing is the Cu/Zn ratio - if you add 1:3, 1:1, 3:1 or whatever so.
Doing so seems also too make a difference. The Heterantera seems to prefer more zn rich dosing like 1:2 or so. If you dose a 2:1 ratio the plant seem to get in trouble.
 

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Discussion Starter · #19 ·
hi,
got all problems finaly fixed.:third:
The reason for the problems was the substrate, it released something that was toxic :eek: for the plants. So yes, it was a toxicity.

I replaced the substrate and still few days later nearly all plants were growing healthy. (still a few needed some days longer for recovering). I also improved the fertiliser mix a little bit and it works now fine.
The both images shown average 5 - 6days growth rate.


So if you also consider some strange growth problems in yours tank that you can´t track down, perhaps also take a look at yours substrate, too. It could be in some cases a trouble maker as well.
 
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